Interleaved high step-up DC-DC converter with three-winding coupled inductors for renewable energy system

An interleaved high step-up DC-DC converter with three-winding coupled inductors and voltage multiplier modules is proposed for high voltage gain and high efficiency applications. The configuration integrates the techniques of winding-cross-coupled inductors, voltage multiplier modules and interactive using the clamp capacitors. The converter achieves high voltage gain without operating at extreme duty ratio. The switch voltage stress is greatly lower than the output voltage such that the low-voltage-rated MOSFETs with low conduction resistor are available to reduce the conduction losses. The output-diode reverse-recovery problem is alleviated due to the leakage inductances of the coupled inductors. The leakage energy of the coupled inductors is recycled such that the voltage spikes on the power switches are avoided and the efficiency is improved. The input current ripple is decreased due to the interleaved operation. A 1000 W experimental prototype with 36 V input and 400 V output is built and tested to verify the effectiveness of the proposed converter.